Rolling bearing unit with tone wheel

ABSTRACT

A bearing unit with tone wheel includes a first seal member made from a metal plate having an elastic member, and a second seal member provided outside the first seal member and placed in sliding contact with the elastic member. The tone wheel is attached to the outside face of the second seal member.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of application Ser. No. 08/787,588 filedJan. 22, 1997 and now allowed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to a rolling bearing unit with tonewheel which rotatably support a vehicle wheel with reference to thesuspension apparatus while detecting the rotating speed of the vehiclewheel supported by this rolling bearing unit.

2. Description of the Related Art

A rolling bearing unit with tons wheel disclosed for example in JPUtility Model Publication KOKAI No. HS-27679 and JP Patent PublicationKOKAI No. 64-21219 is known in the art to support a vehicle wheel withreference to the suspension apparatus while detecting the rotating speedof the vehicle wheel to control the antilock brake system (ABS) ortraction control system (TCS).

The rolling bearing unit with tone wheel disclosed in the publicationmentioned above is constructed as shown in FIG. 1.

There is a hub 1 having at its axially outer end portion (the widthwiseouter end portion when installed in the vehicle, the left end portion inFIG. 1) an outer peripheral surface formed with a flange 2 to fix thevehicle wheel (not shown) to it.

The hub 1 has, at its intermediate portion, an outer peripheral surfaceformed with an inner ring raceway 3 a, and at its axially inner endportion (the widthwise central side end portion when installed, in thevehicle; the right end portion in FIG. 5) an outer peripheral surfacefitted with an inner ring 4 formed with an inner ring raceway 3 b on itsouter peripheral surface. The hub 1 and inner ring 4 form a rotatinginner ring member or assembly.

Disposed on the outer peripheral surface of the stationary outer ring 5is a mount portion 6 which supports the outer ring 5 to the suspensionapparatus, and disposed on the inner peripheral surface of the outerring 5 is a plurality of outer ring raceways 7 d, 7 b. Disposed betweenthe outer ring raceways 7 a, 7 b and the inner ring raceways 3 a, 3 bare a plurality of rolling elements 8 to rotatably support the hub 1 onthe inner side of the outer ring 5 which is supported by the mountportion 6 on the suspension apparatus.

Seal rings 9, 10 are fitted and secured to the opposite opening portionsof the outer ring 5 such that the seal rings 9, 10 have an innerperipheral edges in sliding or rubbing contact with the outer peripheralsurface of the inner ring 4 and hub 1, respectively, so that rain waterand muddy matter are prevented from entering the space inside the outerring 5 where the rolling elements are installed.

As to the pair of seal rings 9, 10, the seal ring 9 on the axially innerside has a function of preventing the penetration of rain water andmuddy matter, and a function as a tone wheel of detecting the rotatingspeed of the hub 1. Specifically, the seal ring 9 as shown in FIG. 2, isan assembly of the radially inner seal ring 11 fitted into the innerring 4 rotating with the vehicle wheel, and a radially outer seal ring12 fitted into the stationary outer ring 5.

The radially inner seal ring 11 is an assembly of a reinforcing metal 13a and seal member 14 a of rubber or synthetic resin etc. while theradially outer seal ring 12 is an assembly of a reinforcing metal 13 band seal member 14 b of rubber or synthetic rein etc. A reinforcingmetal 13 a has a circular ring portion 15 a and a cylindrical portion 16a bent axially from the inner peripheral edge of the circular ringportion 15 a while the reinforcing metal 13 b has a circular ringportion 15 b and a cylindrical portion 16 b bent axially from the outerperipheral edge of the circular ring portion 15 b. The cylindricalportion 16 a is fitted onto the inner ring 4 while the cylindricalportion 16 b is fitted into the outer ring 5 so that the seal rings 11,12 are fixedly supported by the inner ring 4 and outer ring 5,respectively.

The seal members 14 a reinforced by the reinforcing members 13 a hasperipheral edges in sliding or rubbing contact with the inner peripheralsurface and side face of the mating reinforcing metal 13 b,respectively. The seal members 14 b reinforced by the reinforcingmembers 13 b has a peripheral edge in sliding or rubbing contact withthe outer peripheral surface of the mating reinforcing metal 13 a. Theseal between the outer peripheral portion at the axially inner end ofthe inner ring 4 and the inner peripheral portion at the axially innerend of the outer ring 5 is comprised of a plurality seal lips (threeseal lips in the figure) to secure the sealing performance sufficiently.

In the reinforcing metal 13 a fixedly fitted on the inner ring 4rotating with the vehicle wheel, the circular ring portion 15 a isformed with a number of through-holes 17 spaced apart from each otherwith a uniform space circumferentially. Accordingly, the magneticproperty of the circular ring portion 15 a is changed circumferentiallyalternately with a uniform interval, so that the circular ring portion15 a has a function as tone wheel.

A sensor 18 is supported by the non-rotating portion such as thesuspension apparatus, and the detecting portion of the sensor 18 todetect the rotating speed is faced to the portion where thethrough-holes 17 are formed.

In the case of the rolling bearing unit with tone wheel as mentionedabove, the vehicle wheel fixed to the flange 2 provided on the axiallyouter end portion of the hub 1, can be rotatably supported with respectto the suspension apparatus supporting the outer ring 5.

As the vehicle wheel rotates, the radially inner seal ring 11 fittedonto the inner ring 4 rotates, resulting in that the output of thesensor 18 opposed to the radially inner seal ring 11 changes. Thefrequency at which the output of the sensor 18 changes is proportionalto the rotating speed of the vehicle wheel. Accordingly, the outputsignal of the sensor 18 is input to the controllers (not shown) toobtain the rotating speed of the vehicle wheel to suitably control theABS and TCS.

In the case of the prior art rolling bearing unit with tone wheel asmentioned above, both of the radially inner and outer seal rings 11, 12are provided with the seal member 14 a, 14 b, respectively. Therefore,the seal rings 11, 12 must be sufficiently cared during production andhandling. Specifically, the sial member 14 a supported by thereinforcing metal 13 a of the radially inner seal ring 11 whichfunctions as a tone wheel must be cared so that it is not damaged bymuddy water splashing against it during the movements of vehicle. Thisis referred to as muddy water proof.

In addition, the seal members 14 a, 14 b of the seal rings 11, 12 mustbe sufficiently cared so that their peripheral edges or tip ends are notdamaged during the time of period from the production to the assemblingthem between the outer peripheral surface of the inner ring 4 and theinner peripheral surface of the outer ring 5.

These cares will lead to cost-up of the rolling bearing unit with tonewheel having the radially inner seal ring 11.

In addition, the seal ring 9 installed in the rolling bearing unit withtone wheel can achieve a sufficient seal performance while the rotatingspeed of the vehicle wheel is detected, but unavoidably increases theproduction cost. Specifically, since the resilient members 14 a, 14 bare provided adjacent to the pair of reinforcing plate 13 a, 13 b of theseal ring 9, the production processes of the inner seal ring 11 and theouter seal ring 12 are so inconvenient to increase the cost of the sealring 9 comprising the inner and outer seal rings 11, 12 in assembly.

In order to prevent such cost increase, the resilient member 20 as shownin FIG. 3, is attached to only the stationary seal ring 19 fitted andsecured to the stationary ring such as the outer ring 5, and theresilient member 20 is provided with seal lips 21 in sliding or rubbingcontact with the surface of the slinger 22 fitted and secured to therotating ring such as the inner ring 4. In such a construction, however,no cutout such as through hole, notch could be formed in the portion ofthe slinger 22 with which the seal lips 21 are in sliding or rubbingcontact, and therefore the function for tone wheel could not beachieved.

In order that the slinger 22 is provided with the function of tonewheel, the circular ring portion 23 of the slinger 22 is radiallyextended as shown in FIG. 4, and the cutouts such as notches 24 areformed circumferentially with a uniform interval on the tip half portion(upper half portion in FIG. 4) of the circular ring portion 23, so thatthe seal lips 21 are placed in sliding or rubbing contact with the basehalf portion (lower half portion in FIG. 4) of the circular ring portion23.

However, in such a structure, the size in the radial direction of thecircular ring portion 23 must be sufficiently large to secure theportion enough in size for sliding or rubbing contact with the seal lips21, and a step portion 25 must be formed in the stationary ring such asouter ring 5 to avoid interference with the circular ring portion 23.

It is inconvenient to form the stepped portion 25 in the stationary ringmade of a hard material such as bearing steel, leading to cost-up.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a bearing unit withtone wheel having a first seal member made from a metal plate having anelastic member, and a second seal member provided outside the first sealmember and placed in sliding contact with the elastic member and a tonewheel attached to the outside face of the second seal member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of one example of the prior art rollingbearing unit with tone wheel.

FIG. 2 is an enlarged view of Section II in FIG. 1.

FIG. 3 is an enlarged view similar to FIG. 2 in another example of theprior art rolling bearing unit with tone wheel.

FIG. 4 is an enlarged view similar to FIG. 2 in an example of therolling bearing unit with tone wheel which was produced prior to thepresent invention.

FIG. 5 is a cross sectional view of one example in the embodiments ofthe present invention.

FIG. 6 is an enlarged view of the portion having a slinger and seal ringassembly to which a tone wheel is attached.

FIG. 7 is a cross sectional view of another example in the embodimentsof the present invention, similar to FIG. 6.

FIG. 8 is a cross sectional view of another example in the embodimentsof the present invention, similar to FIG. 6.

FIG. 9 is a cross sectional view showing another example of theembodiments of the present invention.

FIG. 10 is an enlarged view of Section X in FIG. 9.

FIG. 11 is a right side view of the slinger and tone wheel assembly ofFIG. 10.

FIG. 12 is an enlarged view similar to FIG. 10 to show another exampleof the embodiments of the present invention.

FIG. 13 is a view similar to FIG. 11 to show another example.

FIG. 14 is an enlarged view similar to FIG. 10 to show another exampleof the embodiments in the present invention.

FIG. 15 is a view similar to FIG. 11 to show another example.

FIG. 16 is an enlarged view similar to FIG. 10 to show another example.

FIG. 17 is an enlarged view similar to FIG. 10 to show another example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The rolling bearing unit with tons wheel in the first embodiment of thepresent invention comprises, like the conventional rolling bearing unitwith tone wheel as mentioned above, an outer ring member which isstationary during use and has an inner peripheral surface formed with anouter ring raceway, an inner ring member which is rotatable during useand has an outer peripheral surface formed with an inner ring raceway, aplurality of rolling elements provided between the outer ring racewayand inner ring raceway, a seal ring fitted and secured into the innerperipheral surface at an end portion of the outer ring member to cover agap extending circumferentially between the inner peripheral surface ofthe outer ring member and the outer peripheral surface of the inner ringmember at the end portion thereof, and a tone wheel made from a magneticplate in a generally annular shape to have a magnetic property changingcircumferentially alternately with a uniform interval and fitted andsecured to the outer peripheral surface at the one end of the inner ringmember.

In the rolling bearing unit with tone wheel of the embodiment, theslinger is made in a generally annular shape and in a L-shape in crosssection, and has a radially inner cylindrical portion formed in itsinner peripheral edge portion and fitted onto the outer peripheralsurface at the one end of the inner ring member, and an radially outercircular ring portion bent from the outside end edge of the radiallyinner cylindrical portion to extend radially outwards.

Specifically, a generally annular reinforcing metal in the L-shape incross section of the seal ring is provided on the inner peripheralsurface of the end portion of the stationary outer ring member, and hasa radially outer cylindrical portion on its outer peripheral edgeportion fitted into the inner peripheral surface of the end portion ofthe outer ring member, and a radially inner circular ring portion bentfrom the radially outer cylindrical portion extending radially inwardswith reference to the inner peripheral surface of the end portion of theouter ring member at a position axially outer of the rotatable circularring portion, that is the circular ring portion of the slinger.

The seal member is fixed generally along the periphery of the stationarycircular ring portion, that is the circular ring portion of the sealring, and has seal lips having tip ends placed in sliding or rubbingcontact with the slinger.

At least one seal lip has its tip end in sliding or rubbing contact withthe inside face of the rotatable circular ring portion.

The tone wheel has an engagement portion formed on the outer peripheraledge portion thereof and attached and secured to the outside face of therotatable circular ring portion with the engagement portion engaged withthe outer peripheral edge of the rotatable circular ring portion.

The rolling bearing unit with tone wheel of the embodiment constructedas above rotatably supports the vehicle wheel with reference to thesuspension apparatus, and detects the rotating speed of the vehiclewheel in a similar member as the conventional bearing units with tonewheel.

Particularly, the seal member is fixed only to the reinforcing metal andnot to the slinger in the rolling bearing unit with tone wheel in thepresent embodiment. Only the tone wheel is attached to the outside faceof the rotatable circular ring portion of the slinger. Accordingly, itis easy to produce and handle the slinger and tone wheel, leading to thecost reduction of the rolling bearing unit with tone wheel.

FIGS. 5 and 6 show a first example of an embodiment of the presentinvention. Outer ring raceways 7 in double rows are formed on an innerperipheral face of an outer ring 5 a which does not rotate during use.Moreover, respective inner ring raceways 3 are formed on outerperipheral faces of a pair of inner rings 4 a which rotate during use,and which are fitted over an axle (not shown in FIG. 5). A plurality ofrolling elements 8 are respectively provided between each of therespective outer ring raceways 7 and the inner ring raceways 3, therebyrotatably supporting the axle inside the outer ring 5 a.

With the example shown in FIG. 5, balls are used for the rollingelements 8. However in the case of a rolling bearing unit for heavyvehicles, tapered rollers may be used for the rolling elements 8.

A seal ring 19 is internally fitted to an inner peripheral face on theaxially inner end portion of the outer ring 5 a, so as to cover aroundthe whole periphery of a space 20 between the inner peripheral face onthe axially inner end portion of the outer ring 5 a and the outerperipheral face on the axially inner end portion of the inner ring 4 a.The seal ring 19 is made from a reinforcing member 21 formed from ametal plate, and a seal member 22 formed from a resilient material suchas rubber or an elastomer or the like. The reinforcing member 21 isformed in an overall annular shape of L-shape in cross-section, with aradially outer cylindrical portion 23 formed on an outer peripheral rimportion, and a fixed side disc portion or circular ring portion 24 bentradially inwards at right angles from an end rim (left end rim in FIGS.5 and 6) of the radially outer cylindrical portion 23. With the metalshell 21, the radially outer cylindrical portion 23 is internallysecured to the inner peripheral face on the axially inner end portion ofthe outer ring 5 a, with the fixed side disc portion 24 protrudingradially inwards therefrom. The seal member 22 is securely supported bythe fixed side disc portion 24, and has a plurality (shown typically asthree in the figures) of seal lips 25 a, 25 b and 25 c.

A slinger 26 formed in an overall annular shape of L-shape incross-section, is externally secured to the outer peripheral face on theaxially inner end portion of the inner ring 4 a. The slinger 26 isformed in an overall annular shape of L-shape in cross-section from ametal plate such as steel plate or stainless steel plate, and has aradially inner cylindrical portion 27 formed on an inner peripheral rimportion thereof, and a rotating side disc portion or circular ringportion 28 bent radially outwards at right angles from an end rim (rightend rim in FIGS. 5 and 6) of the radially inner cylindrical portion 27.With the slinger 26, the radially inner cylindrical portion 27 isexternally secured to the outer peripheral face on the axially inner andportion of the inner ring 4 a, with the rotating side disc portion 28protruding radially outwards therefrom.

With the slinger 26 externally secured in this way to the outerperipheral face an the axially inner end portion of the inner ring 4 a,the rotating side disc portion 28 is further to the opening side (rightside in FIGS. 5 and 6) of the space 20 than the fixed side disc portion24. Furthermore, with the three seal lips 25 a, 25 b and 25 c providedon the seal member 22, the tip rim of the seal lip 25 a providedradially furthest outward, rubs against the inside face (left side facein FIGS. 5 and 6) of the rotating side disc portion 28, while the tiprims of the other two seal lips 25 b, 25 c rub against the outerperipheral face of the inner diameter cylindrical portion 27.

A tone wheel 29 is fixed to the outside face (right side face in FIGS. 5and 6) of the rotating side disc portion 28, by means of a resilientmember 30 made for example from synthetic resin or hard rubber. The tonewheel 29 is formed by punching a magnetic material such as carbon steelplate having a thickness of for example 0.6-2.0 mm, so as to give aplurality of cut-outs 31 in the form of openings in an outer peripheralrim, at even spacing around the circumference. The tone wheel 29 thushas a comb teeth form.

The punching process is preferably carried out from the inside face(left side face in FIGS. 5 and 6) of the tone wheel 29 to the outsideface (right side face in FIGS. 5 and 6). The reason for this is so thatthe edges of the respective cut-outs 31 are sharp on the side facing thesensor 18 (refer to FIG. 1), thus improving the detection accuracy ofthe sensor 18.

The resilient member 30 is wrapped around the tone wheel 29 and molded.That is to say, the resilient member 30 covers both the inner and outerperipheral portions of the tone wheel 29 as well as the inner peripheralhalf on the outside face, also filling the respective cut-outs 31, thusgiving an overall single body with the tone wheel 29 embedded therein.Moreover, an engagement portion 32 of L-shape in cross-section, isformed completely or intermittently around an outer peripheral rimportion of the resilient member 30 on the inside face (left side face inFIGS. 5 and 6). The tone wheel 29 is thus fixed to the outside face ofthe rotating side disc portion 28, by engaging the engagement portion 32with the outer peripheral rim portion of the rotating side disc portion28.

With the rolling bearing unit with tone wheel according to the presentinvention constructed as described above, the seal member 22 is fixed tothe reinforcing metal 21 only, and not to the slinger 26. Moreover, withthe rotating side disc portion 28 of the slinger 26 has the tone wheelattached only to its outside face. Consequently, the manufacture andhandling of the slinger 26 and the tone wheel 29 is simplified, thusenabling a reduction in the cost of the rolling bearing unit with tonewheel. That is to say, in the case of the construction of first exampleshown in FIGS. 5 and 6, the tore wheel 29 is fixed to the slinger 26 bymeans of the resilient member 30, which has the sole role of connectingthe tone wheel 29 to the slinger 26, and has no sealing function.Consequently, the quality of the resilient member 30 need not be limitedto that to maintain a seal. Moreover, since small scratches on theresilient member 30 present no problem, there is no need for specialcare when handling the slinger 26 fitted with the tone wheel 29. Inother words, care is only required when handling the seal ring 19, andhence parts management and handling is simplified.

FIG. 7 shows a second example of the first embodiment of the presentinvention. With this example, the resilient member 30 (FIGS. 5 and 6) isomitted, and instead the tone wheel 29 is fixed to the outside face(right side face in FIG. 7) of the rotating side disc portion orcircular ring portion 28 of the slinger 26, by means of engagementportions 32 a formed by bending back an outer peripheral rim of a tonewheel 29. That is to say, the engagement portions 32 a are formed bybending back the tip portions of finger portions 33 existing betweenadjacent cut-outs 31 around the periphery at the outer peripheral rimportion of the tone wheel 29, at the outer peripheral rim of therotating side disc portion 28, so that the tone wheel 29 is fixed to theoutside face of the rotating side disc portion 28 by these engagementportion 32 a. If there is the possibility of interference of theengagement portions 32 a with the seal ring 19, then a part of themagnetic metal plate forming the tone wheel 29 can be made thinner atthe portion forming the engagement portions 32 a. This thinningoperation can be carried out by coining, prior to forming the engagementportion 32 a, or can be carried out afterwards by machining with alathe. Other details of the operation and construction are the same asfor the beforementioned first example.

FIG. 8 shows a third example of the embodiment of the present invention.With this example, a plurality of through holes 34 are formed in amagnetic metal plate tone wheel 29 a, at even spacing around thecircumference. An engagement portion 32 b is formed by bending an outerperipheral rim portion of the tone wheel 29 a at the outer peripheralrim of the rotating side disc portion 28, so that the tone wheel 29 a isfixed to the outside face (right side face in FIG. 8) of the rotatingside disc portion 28 by means of the engagement portion 32 b.

If the operation of bending back the outer peripheral rim portion of thetone wheel 29 a around the whole periphery is inconvenient, then aplurality of cut-outs may be formed in the outer peripheral rim portion,so that the bending back operation can be carried out with less forceand without distortion of the tone wheel 29 a. Other details of theoperation and construction are the substantially same as for the secondexample.

Some seal rings are disclosed in the following part of thespecification.

The seal ring assembly with tone wheel of the present embodiment coversthe open end portion of the space between the peripheral surface of thestationary and rotatable rings or ring members, while detecting therotating speed of the rotatable ring.

The seal ring assembly with tone wheel comprises a seal ring fixed to aperipheral surface of the stationary ring, a slinger fixed to aperipheral surface of the rotatable ring, and a tone wheel supported byand fixed to the slinger.

The seal ring comprises a reinforcing metal comprising a stationarycylindrical portion fitted and fixed to the peripheral surface of thestationary ring and a stationary circular ring portion bent toward theperipheral surface of the rotatable ring from the and edge of thestationary cylindrical portion, and a resilient member having a seal lipprovided generally along the periphery of the reinforcing metal. Theslinger comprises a rotatable cylindrical portion fitted and fixed tothe peripheral surface of the rotatable ring, and a rotatable circularring portion or disc portion bent toward the peripheral surface of thestationary ring from the end edge of the rotatable cylindrical portion,but no resilient member.

The peripheral surface of the rotatable cylindrical portion and one sidesurface of the rotatable circular ring portion with which the tip end ofthe seal lip is placed in sliding or rubbing contact are made flat. Thetone wheel is provided adjacent to the other side face of the rotatablecircular ring portion, and the magnetic property of the tone wheelchanges alternately circumferentially with a uniform interval. The tonewheel can be mounted to the other side face of the circular ring portionby welding, bending or crimping etc.

In the seal ring assembly with tone wheel as mentioned above, the sealring is placed fitted and fixed to the peripheral surface of thestationary ring, and the slinger is to the peripheral surface of therotatable ring, and the seal lips of the resilient member of the sealring are placed in sliding or rubbing contact with the surfaces of theslinger.

The tone wheel attached to the other side face of the rotatable circularring portion of the slinger is faced to a detecting portion of thesensor.

In this condition, the seal ring assembly comprising the seal ring andslinger covers the space between the peripheral surface of thestationary and rotatable rings or ring members.

Accordingly, no foreign matter can enter the space, and no grease filledin the space leaks out of the space.

The slinger itself has no function for tone wheel in the seal ringassembly in the embodiments, so that the tip end edges of the resilientseal lips attached to the seal ring can be placed in sliding or rubbingcontact with the flat surface even without increasing the side in theradial direction of the slinger.

The resilient member is attached to the seal ring and not to theslinger, so that the whole cost of the seal ring assembly can bereduced.

The tone wheel is fixed to the other side face of the circular ringportion of the slinger, so that the function of the tone wheel issecured.

FIGS. 9 through 11 show a first example of a second embodiment of thepresent invention. Outer ring raceways 27 in double row are formed on aninner peripheral face of an outer ring or fixed ring 26, whilerespective inner ring raceways 29 are formed on the outer peripheralfaces of inner rings or rotating rings 28. A plurality of rollingelements 8, retained by means of a retainer or cage 30, are rotatablyprovided between each of the respective outer ring raceways 27 and theinner ring raceways 29. When fitted to a vehicle, the outer ring 26 isinternally secured to a bearing housing 31 of a suspension unit, and adrive shaft (not shown in the figures) for rotating a vehicle wheel, isinserted through the respective inner rings 28.

Respective seal ring assemblies 32 are provided between the innerperipheral faces on the axially opposite ends portions of the outer ring26 and the outer peripheral faces on the corresponding end portions ofthe respective inner rings 28, to thereby isolate from the outside, aspace 33 in which the respective rolling elements 8 are provided betweenthe inner peripheral face of the outer ring 26 and the outer peripheralfaces of the inner rings 28.

The seal ring assemblies 32 are of the same construction, and areinserted symmetrical with each other. Consequently, the mass productioneffect enables a reduction in cost compared to the case where seal ringassemblies 32 for the inner and outer end portions are made different.It should be noted, however, that a tone wheel 34 is fitted to the sealring assembly 32 on the axially inner end (right side end in FIG. 9),thus giving the seal ring assembly with tone wheel according to thepresent invention. A description of this seal ring assembly with tonewheel is given hereunder.

The seal ring assembly with tone wheel incorporates a seal ring 35 fixedto an inner peripheral face on an axially inner end portion of the outerring 26, a slinger or frame metal 36 fixed to an outer peripheral faceon the axially inner end portion of the inner ring 28, and a tone wheel34 securely supported by the slinger 36.

The seal ring 35 is made from a reinforcing metal 37 and a resilientmember 38. The reinforcing metal 37 is formed in an overall annularshape of L-shape in cross-section by bending a metal plate such as asteel plate. The reinforcing metal 37 incorporates a fixed sidecylindrical portion 39 internally secured to the inner peripheral faceon the axially inner end portion of the outer ring 26, and a fixed sidedisc portion 40 bent radially inwards from the axially outer end rim ofthe fixed side cylindrical portion 39, towards the outer peripheral faceof the inner ring 28.

Moreover, the resilient member 38, formed from a rubber or an elastomeror the like, has a plurality (shown typically as three in the figures)of seal lips 41 a-41 c, and is adhered for example by thermal bonding,fully around the reinforcing metal 37.

The slinger 36 also is formed in an overall annular shape of L-shape incross-section by bending a metal plate such as a steel plate. Theslinger 36 incorporates a rotating side cylindrical portion 42externally secured to the outer peripheral face on the axially inner endportion of the inner ring 28, and a rotating side disc portion 43 bentradially outward from the axially inner end rim of the rotating sidecylindrical portion 42, towards the inner peripheral face of the outerring 26.

The slinger 36 is made solely from metal plate, and does not have aresilient member 38 as with the seal ring 35. Moreover, recesses orprotrusions such as through holes or cut-outs are not formed in eitherof the rotating side cylindrical portion 42 or the rotating side-discportion 43, so that the parts rubbed by the tip rims of the seal lips 41a-41 c at the outer peripheral face of the rotating side cylindricalportion 42 and the inside face or axially outer face of the rotatingside disc portion 43 are formed as smooth flat surfaces.

The tone wheel 34 is made in an overall disc shape or circular ringshape by punch forming a magnetic metal plate such as a steel plate. Aplurality of cut-outs 24 forming respective openings in the outerperipheral rim, are formed at even spacing around the circumference, sothat the magnetic properties around the circumferential direction changealternately and at even spacing.

The tone wheel 34 is fixed to the outside face or axially inner face ofthe rotating side disc portion 43 by welding, for example spot welding,or by bonding. When thus secured, the tone wheel 34 and the slinger 36are concentric with each other.

Since the tone wheel 34 and the slinger 36 are exposed for example towater and mud from the road, etc., then corrosion prevention must beconsidered. Consequently, when made from metal plate such as SPCC,corrosion prevention treatment such as chrome plating must be carriedout on the surface. Alternatively the parts may be made completely frommagnetic stainless steel plate such as SUS430. With the chrome platingcorrosion prevention treatment, in the case where the tone wheel 34 andthe slinger 36 are connected together by welding, the plating treatmentis carried out after welding.

Since the welded portion is opposite to or far from the rolling elements8 with reference to the resilient member 38 of the sealing device, it isnot necessary for the welded portion to be air tight. Therefore, spotwelding can be used for the welding. With spot welding, the attachmentstrength is strong and attachment cost is low. Moreover distortion ofthe tone wheel 34 and the slinger 36 due to heating is minimal, so thatseal performance is only marginally impaired. Consequently, this isconsidered the ideal method for connecting the tone wheel 34 to theslinger 36.

The seal ring assembly with tone wheel according to the presentinvention constructed as described above is fitted, as shown in FIGS. 9and 10, between the inner peripheral face on the axially inner endportion of the outer ring 26, and the outer peripheral face on theaxially inner end portion of the inner ring 28, with the seal ring 35internally secured to the inner peripheral face of the outer ring 26,and the slinger 36 externally secured to the outer peripheral face ofthe inner ring 28.

Moreover, in the assembled condition, where the plurality of seal lips41 a-41 c of the resilient member 38 makes up the seal ring 35, the seallips 41 a, 41 b rub against the outer peripheral face of the rotatingside cylindrical portion 42 of the slinger 36, while the remaining seallip 41 c rubs against the inside face or axially outer face of therotating side disc portion 43. At the outside face or axially inner faceof the tone wheel 34 which is fixed to the axially inner face of therotating side disc portion 43 of the slinger 36, a detection portion ofa sensor 18 a is positioned so as to face the radially outer halfportion formed with the cut-outs 24.

With the seal ring assembly with tone wheel fitted in this way betweenthe inner peripheral face on the axially inner end portion of the outerring 26 and the outer peripheral face on the axially inner end portionof the inner ring 28, the composite seal ring assembly 32 comprising theseal ring 35 and the slinger 36, covers between these inner and outerperipheral faces, so that as well as preventing the ingress of foreignmatter into the space 33 between the two peripheral face pairs, and thatgrease filled into the space 33 is prevented from leaking to theoutside.

Moreover, when the inner ring 28 rotates together with the vehiclewheel, so that the tone wheel 34, which is fixed to the inner ring 28 bymeans of the slinger 36 rotates, the output signal from the sensor 18 achanges with a frequency proportional to the rotational speed of thevehicle wheel. Therefore, if the output signal from the sensor 18 a isinput to a controller (not shown in the figures), the rotational speedof the vehicle wheel can be obtained, thus enabling appropriate controlof an anti-lock braking system (ABS) or a traction control system (TCS).

In particular, with the seal ring assembly with tone wheel according tothe present invention, the slinger 36 itself does not have the functionof a tone wheel, and in spite of the fact that the radial dimension ofthe slinger 36 is not particularly large as shown with the constructionof FIG. 4, the tip rims of the respective seal lips 41 a-41 c providedon the resilient member 38 provided adjacent to the seal ring 35, canstill rub against a flat smooth surface. Consequently, it is notnecessary to form a step 25 of (FIG. 4) or the like in the fixed outerring as with the construction shown in FIG. 4.

Moreover since the resilient member 38 is only fixed to the seal ring35, with no resilient material fixed to the slinger 36, then the overallcost for the seal ring assembly can be reduced.

In the case where the tone wheel 34 and the slinger 36 are connectedtogether by spot welding, then in order to minimize the influence on theseal performance, of distortion of the slinger 36 due to heat generatedat the time of welding, the two members 34 and 36 are preferablyconnected at a part away from the portion where the respective seal lips41 a-41 c are placed in sliding contact. For example, with theconstruction shown in FIGS. 9 to 11, the radially inner half portion ofthe tone wheel 34 (the portion radially inwards of the portion with thecut-outs 24) and the radially inner half portion of the rotating sidedisc portion 43 of the slinger 36, are spot welded at several locationsaround the circumferential direction. If the location of the spot weldsis controlled in this way, then even with slight distortion of theslinger 36, this will give negligible impairment to the sealperformance.

FIGS. 12 and 13 show a second example of the second embodiment of thepresent invention. With this example, the cross-sectional shape of theslinger 36 a is J-shaped. That is to say, a radially outer cylindricalportion 44 is formed by bending a half portion on the outer diameterside of the rotating disc portion 43, at right angles in the samedirection as the rotating cylindrical portion 42. Moreover, tip rims ofthree seal lips 41 a, 41 b and 41 c of a seal ring 35 a respectively rubagainst the outer peripheral face of the rotating side cylindricalportion 42, the inside face or axially outer face of the rotating sidedisc portion 43, and the outer peripheral face of the radially outercylindrical portion 44. Moreover, the half portion on the outer diameterside of the tone wheel 34 which is fixed to the outside face or axiallyinner face of the rotating side disc portion 43 by welding or bonding orthe like, protrudes radially further outward (in the upward direction ofFIGS. 12 and 13) than the outer peripheral face of the outer diametercylindrical portion 44.

With the example constructed in this way, the passage between the sealring 35 a and the slinger 36, through which foreign matter can enterfrom outside to the interior of the space 33, and which is the cause ofleakage of grease filled inside the space 33, is bent. Therefore,compared to the abovementioned first example, the seal performance ofthe composite seal ring 32 is further improved. Moreover a tone wheel 34secured to a slinger 36 a also functions as an auxiliary slinger forslinging and throwing muddy water and the like when the vehicle wheel isrotating. Hence the seal performance is even better. Other details ofthe operation and construction are substantially the same as for thebeforementioned first example.

FIGS. 14 and 15 show a third example of the second embodiment accordingto the present invention. With this example, a rotating disc portion 43a of a slinger 36 b extends radially outwards from an axially outer endrim of a rotating cylindrical portion 42 a. Moreover, a tone wheel 34 isprovided adjacent to an axially inner end face of the rotating side discportion 43 a, and crimped portion 45 is formed by crimping so as toexpand radially outwards, at several locations around the periphery ofthe rotating cylindrical portion 42 a (or around the whole periphery).By means of this crimped portion 45, the inner peripheral rim of thetons wheel 34 is restrained. Moreover, of three seal lips 41 a, 41 b and41 c of a seal ring 35, tip rims of the seal lips 41 a, 41 b arerespectively rubbed against an outer peripheral face on an axially innerend portion of an inner ring 28, while a tip rim of the seal lip 41 c isrubbed against the axially outer face of the rotating side disc portion43 a.

With the present example, since the tip end portion (right end portionin FIG. 14) of the rotating cylindrical portion 42 a is made to protrudefrom the axially inner face of the tone wheel 34, and the crimpedportion 45 is formed from this protruding portion, then the supportstrength for the tone wheel 34 can be increased. However, since theforce tending to separate the tone wheel 34 from the rotating discportion 43 a is only slight, there is no real need to have the tip endportion protruding from the axially inner face of the tone wheel 34.Moreover, having no protrusion is advantageous from the point ofpreventing interference between the rotating cylindrical portion 42 aand the sensor 18 a (FIG. 9). Other details of the construction andoperation are the substantially same as for the abovementioned firstexample.

With the abovementioned respective examples, the descriptions have allbeen for the case where the fixed ring is the outer ring 26 and therotating ring is the inner ring 28. The present invention may however becarried out with an opposite arrangement, with the fixed inner ring andthe outer rotating ring. In this case, inwards and outwards for theradial directions, will be opposite to the examples shown in thefigures. Specifically, in FIGS. 16 and 17, the outer ring 26 isrotatable while the inner ring 28 is stationary. The slinger 36 and tonewheel 34 are mounted to the outer ring 26 while the seal ring 35 ismounted to the inner ring 28. A spot weld 60 is shown in the figures.

What is claimed is:
 1. A rolling bearing unit with tone wheelcomprising: an outer ring member which is stationary during use and hasan inner peripheral surface formed with an outer ring raceway, an innerring member which is rotatable during use and has an outer peripheralsurface formed with an inner ring raceway, a plurality of rollingelements provided between the outer ring raceway and inner ring raceway,a seal ring fitted and secured into the inner peripheral surface at anend portion of the outer ring member to cover a gap extendingcircumferentially between the inner peripheral surface of the outer ringmember and the outer peripheral surface of the inner ring member at theend portion thereof, a tone wheel made from a magnetic plate in agenerally annular shape to have a magnetic property changingcircumferentially alternatively with a uniform interval and fitted andsecured to the outer peripheral surface at the one end of the inner ringmember, a slinger made in a generally annular shape and in a L-shape incross section, and having a radially inner cylindrical portion formed inits inner peripheral edge portion and fitted onto the outer peripheralsurface at the end of the inner ring member and a radially outercircular ring portion bent from an outside end edge of the radiallyinner cylindrical portion to extend radially outwards, the seal ringhaving a generally annular reinforcing metal in a L-shape in crosssection provided on the inner peripheral surface of the end portion ofthe stationary outer ring member, the reinforcing metal having an outerperipheral edge portion formed with a radially outer cylindrical portionfitted into the inner peripheral surface of the end portion of the outerring member, and a radially inner circular ring portion bent from theradially outer cylindrical portion extending radially inwards withreference to the inner peripheral surface of the end portion of theouter ring member at a position axially outer of the rotatable circularring portion of the slinger, the circular ring portion of thereinforcing metal having a seal member fixed generally along theperiphery thereof, and having seal lips with tip ends placed in slidingcontact with the slinger, at least one seal lip having its tip end insliding contact with an inside face of the circular ring portion of theslinger, and the tone wheel having an outer peripheral edge portionformed with an engagement portion thereon and provided adjacent to anoutside face of the rotatable circular ring portion with the engagementportion engaged with the outer peripheral edge of the circular ringportion of the slinger.
 2. A bearing unit comprising: a bearing sectionhaving outer and inner rings one of which is a stationary ring and theother is a rotatable ring, the outer ring having a first end portionformed with an inner peripheral surface and the inner ring having afirst end portion formed with an outer peripheral surface, such that agap extends circumferentially between the inner peripheral surface ofthe outer ring and the outer peripheral surface of the inner ring, saidinner ring has a second end portion flush with a second end portion ofsaid outer ring, a seal assembly having a slinger and a tone wheeldisposed in an outer diameter circle of the outer ring and crimped tothe slinger, a seal ring fitted and fixed to the peripheral surface atthe end portion of the stationary ring and having seal lips to cover thegap, the slinger comprising a cylindrical portion and a circular ringportion, the cylindrical portion fitted and fixed to the rotatable ringto be rotatable together with the rotatable ring and having first andsecond end edges, the first end edge being adjacent to the seal ring andthe second end edge being crimped to the tone wheel for fixing, thecircular ring portion bent toward the stationary ring from the first endedge of the cylindrical portion, the circular ring portion having firstand second side faces, the first side face being smooth and adjacent tothe seal ring and at least one of the seal lips having a tip end placedin sliding contact with the first side face, the tone wheel is flushwith the second end portion of the inner ring and is made from amagnetic metal plate and provided adjacent to the second side face ofthe circular ring portion and concentric with the cylindrical portionand having a plurality of cutouts circumferentially arranged to providemagnetic properties changing alternately circumferentially with auniform interval.
 3. A bearing unit comprising: a bearing section havingouter and inner rings one of which is a stationary ring and the other isa rotatable ring, the outer ring having an end portion formed with aninner peripheral surface and the inner ring having an end portion formedwith an outer peripheral surface, such that a gap extendscircumferentially between the inner peripheral surface of the outer ringand the outer peripheral surface of the inner ring, a seal assemblyhaving a slinger and a tone wheel disposed in an outer diameter circleof the outer ring and crimped to the slinger, a seal ring fitted andfixed to the peripheral surface at the end portion of the stationaryring and having seal lips to cover the gap, the slinger comprising acylindrical portion and a circular ring portion, the cylindrical portionfitted and fixed to the rotatable ring to be rotatable together with therotatable ring and having first and second end edges, the first end edgebeing adjacent to the seal ring and the second end edge being crimped tothe tone wheel for fixing, the circular ring portion bent toward thestationary ring from the first end edge of the cylindrical portion, thecircular ring portion having first and second side faces, the first sideface being smooth and adjacent to the seal ring and at least one of theseal lips having a tip end placed in sliding contact with the first sideface, the tone wheel made from a metal magnetic plate and providedadjacent to the second side face of the circular ring portion andconcentric with the cylindrical portion and having a plurality ofcutouts circunferentially arranged to provide magnetic propertieschanging alternately circumferentially with a uniform interval.